Router/modem on off & DLM effects

Right I would like to get this settled once and for all. A lot of confusion and conflicting advice given. This is to do with FTTC, not ADSL.

To start. When I�m not using my router, I like to turn it off. Always done it and never had a problem before. This is only once a day normally.

I have been advised in the past that turning my router off won't affect my line. I have been advised to leave my modem on, as that syncs up with the cabinet and exchange, not the router.

I also have been told that so long as you don't switch your router off more than about, three times a day, then DLM should not see it as a problem.

Today I asked about disconnecting the red Ethernet cable and have been told, that disconnecting the cable from the wan port, would be the same as switching your router off and will register as a disconnection at the exchange. That will trigger DLM and can slow me down.

So what is correct?

Edited by deleted (Wed 02-Jan-13 17:48:00)

As suggested here, this would be better posted in the 'Fibre Broadband' section as both the question and answers are pertinent to many providers?

It depends what your red cable is connected between.

So long as the modem stays powered up, and is physically connected to the VDSL faceplate (or the data extension connector), then you are fine. This connection is normally an RJ11 lead, but I've seen people indicate that the socket can actually accept an RJ45 lead.

If you power down the router, or remove the cable between router & modem (which is what I think you are referring to), then you will lose the PPP connection to your ISP. This cable ought to be an RJ45 cable - so is probably your red one (mine is yellow, so the colour doesn't help identify anything).

Plusnet's in-house connection monitoring tools will see this as a disconnection, because they cannot distinguish PPP disconnections from a resync. However, the Openreach cabinet, and more importantly DLM, will not see this as a disconnection of the VDSL2 sync.

There is no real downside, except...

If you have problems in future, Plusnet will use their in-house tools to try to troubleshoot the problem, and may be fooled by seeing the PPP disconnections. They'll ask you to leave both modem & router switched on & connected, and may therefore be a bit slower at trying to diagnose what the *real* problem is.

If you power down the router, or remove the cable between router & modem (which is what I think you are referring to), then you will lose the PPP connection to your ISP. This cable ought to be an RJ45 cable - so is probably your red one (mine is yellow, so the colour doesn't help identify anything).

Yes that is what I mean. It's like this setup. http://cdn0.mos.techradar.futurecdn.net//classificat...

You must have ADSL as that is what plusnet sends with it. Red is for fibre. http://www.plus.net/support/broadband/hardware/techn...

When I have disconnected my router, PN says it shows up as a line drop. They can't tell if it's me switching off the router of a natural drop. So that is also affecting my speeds to a point.

So does that mean PN's in=house tools are much stricter than BT's? I think some of the PN staff are in need of some training. They all say different things.

Edited by deleted (Wed 02-Jan-13 20:11:17)

I don't think this will be suitable to go there. Thats why I posted it in PN forum but some information may still be relevant to others.

Edited by deleted (Wed 02-Jan-13 20:08:38)

In reply to a post by superspeed:

When I have disconnected my router, PN says it shows up as a line drop. They can't tell if it's me switching off the router of a natural drop. So that is also affecting my speeds to a point.

Plusnet see it as a PPP drop whether the line remains in sync or not.
This won't affect the speeds
If you want to do a quick check look at the lights on the modem - they won't be affected when the router is unplugged so there isn't a line drop

It all depends really. The ISP will see it as a drop in the session so to them it's a disconnection. Certainly on Sky when I was turning the router off and on (around 3 times in a couple of hours) I got put on a higher interleaving depth and lost 7Mbps of sync speed. After around 2 weeks of leaving everything on it went back to normal.

I think the best advice that can be given is to just leave it on.

Technically it shouldn't affect things but certainly the router can impact the line management. We have seen plenty of occasions where using a different router has made the line sync much slower with no explanation why & the line management has kicked in randomly. Nobody seems to know the true extent of the management on FTTC as far as I'm concerned.

If you're leaving the modem on it makes no sense to turn the router off?! It's silly and you will save probably around 10 / 20p on a monthly bill. Especially considering most routers have power saving mode when not in use (which essentially means they use barely anything).

Edited by ukhardy07 (Wed 02-Jan-13 20:37:22)

Yes, the power light and the DSL light stay lit when I disconnect my router from the modem.

I don't switch my router off that many times normally in an hour. Only once but if I have problems like I have been having, it maybe twice.

I have always turned it off and for security. No way am I leaving my computer connected to the web 24/7. Power is getting more expensive and it's a waste of energy but I know what you are saying.

Edit why not? isnt the modem what makes the link with the FTTC and exchange?


Could a PN rep please confirm what you would do.

Edited by deleted (Wed 02-Jan-13 20:57:42)

Just found this on PN website but don't say how much will cause a problem.

. Leave your router switched on
Leaving your router on will make sure you get the best speed and performance from your service.

Don�t switch it off at night! Regularly switching off your router can make it look like your service is disconnecting. If this happens, your broadband speed will be reduced because the exchange thinks your line is unstable and can�t cope with higher speeds. Speed reductions are never permanent, but it can take up to 3 days before your speeds return to normal.

http://www.plus.net/support/broadband/speed_guide/sp...

I don't switch my router off that many times normally in an hour. Only once but if I have problems like I have been having, it maybe twice.

2 times in one hour is plenty to trigger line management.

I have always turned it off and for security. No way am I leaving my computer connected to the web 24/7. Power is getting more expensive and it's a waste of energy but I know what you are saying.

Put a long WPA2 key on the router. No security risk then.

Most PCs in the world are connected to the internet whenever they are on.
Turning a router off isn't a solution here. If you are concerned about your security on your PC you should be using an antivirus and taking precautions online. That's the answer... Ensure your PCs not infected (as you should anyway) and there's no risk.

Power is getting more expensive but a router being on is going to make barely no difference. Boiling less water in the kettle would save you lots lots more or turning the heating dial down by 1 degree. All of which would save you probably 10 / 20 times more money.

Edit why not? Is't the modem what makes the link with the FTTC and exchange?

The modem makes a connection to the local green cabinet.
The router makes a connection to the PPP session with your ISP.
So if you unplug the router then the ISP thinks that you have lost internet connection.
It shouldn't affect things but in experience I have noticed odd things occurring when I turn the router off lots.

All of the sky routers sent for fibre now come with this sticker on them.

http://postimage.org/image/uv53tb5gb/

I just don't understand the need to turn it off still really. Surely it's more of an inconvenience always turning it back on when you want to use a device.

I've never even thought about it though as we have so many people using the connection in my house. So I'd just disturb someone

Edited by ukhardy07 (Wed 02-Jan-13 21:06:55)

2 times in one hour is plenty to trigger line management.

Sorry I should of said in a day. Was not ment to be an hour. Lol

Put a long WPA2 key on the router. No security risk then.

Most PCs in the world are connected to the internet whenever they are on.
Turning a router off isn't a solution here. If you are concerned about your security on your PC you should be using an antivirus and taking precautions online. That's the answer... Ensure your PCs not infected (as you should anyway) and there's no risk.

Power is getting more expensive but a router being on is going to make barely no difference. Boiling less water in the kettle would save you lots lots more or turning the heating dial down by 1 degree. All of which would save you probably 10 / 20 times more money.

Most computers maybe on but it don't mean I have to. I have antivirus, firewall and all that but that is no protection from someone/group, going through your computer. Thats also another reason I don't use wireless and is the cause of many speed problems.

The modem makes a connection to the local green cabinet.
The router makes a connection to the PPP session with your ISP.

So if as first says, then no reason for DLM to kick in. That must mean it's the ISP end making that choice.

I just don't understand the need to turn it off still really. Surely it's more of an inconvenience always turning it back on when you want to use a device.

I have been doing just that for many years and for reasons above, without issue. It seems to be BT's inflexible systems that may have issue with it.

Edited by deleted (Wed 02-Jan-13 21:23:58)

On my 5ghz network wifi outperforms my Ethernet speeds.
WPA2 is very secure.

2 times a day should be okay however I doubt that line management would increase the speed. I have to see a good 7 days + of no dropouts before a speed increase occurs.

That's good if you can get that speed but you can't beat a wired only connection. Much less hassle.

I really have to disagree

Getting cables to all of my devices in a 3 storey house with 6 befrooms would be a nightmare.
I have around 13 devices using wifi at once and nothing wired.
I have no problems what so ever and it's as stable as any wired connection.
Granted at a large distance from the router my speeds slow down considerably but overall I find wifi to be excellent.

I guess you don't have a smartphone / laptop / tablet of any kind where wifi is a must?

I guess you don't have a smartphone / laptop / tablet of any kind where wifi is a must?

I have no need for a smartphone, and typing BS on boringbook. Have a laptop but is connected by wire most of the time. Broadband dongle other times.

I think the more correct spelling is "smart"phone
edit - in case it isn't obvious, meaning it is a phone, as for the "smart" part... well.

Edited by deleted (Wed 02-Jan-13 21:59:14)

In reply to a post by superspeed:

Yes that is what I mean. It's like this setup. http://cdn0.mos.techradar.futurecdn.net//classificat...

Then yes - your red cable is safe to be disconnected with no effect on the VDSL2 sync, or on the DLM monitoring of the line conditions.

Plusnet's internal tools (they create pretty pictures of the PPP session drop/restore) will see each drop of the router, but this information is NOT used by the cabinet, DLM or Openreach. It is more used by the Plusnet support people when they want to troubleshoot your line.

If you *do* encounter line problems in the future, and want help from PN staff to troubleshoot, then you will be well advised to leave the router on then. Otherwise you are fine.

You must have ADSL as that is what plusnet sends with it. Red is for fibre.

Nah - my ADSL kit wasn't supplied by PN, and comes in a variety of colours. But my FTTC kit *was* supplied by PN and is definitely yellow - but it was for the trials 18 months ago, and is a Netgear WNR1000.

When I have disconnected my router, PN says it shows up as a line drop. They can't tell if it's me switching off the router of a natural drop. So that is also affecting my speeds to a point.

The assumption behind the tool, valid when written, was that most people have a combined router/modem, so there isn't an issue of powering one without the other, or of removing the cable between the two. And the number of ADSL customers over FTTC customers means that thinking is still correct for *most* of their customers.

In addition, it does seem that the FTTC installations are, on the whole, in a much better state - perhaps because they are all engineer-installed so far. The PN staff probably don't have to troubleshoot many FTTC lines, so are finding it hard to remember that there *is* a difference.

The important point is that, no matter what PN see (or say to you), there is nothing about their tools that affects DLM, or causes it to restrict your speeds.

So does that mean PN's in=house tools are much stricter than BT's?

In this case, the PN tools are for information, and to help understanding. They don't cause restrictions, so they can't be considered "strict" at all.

I'm sure they'd prefer to monitor sync drops rather than PPP drops, but they just aren't privvy to that information, so do the best they can.

I think some of the PN staff are in need of some training. They all say different things.

There's nothing like hands-on experience to remind you of your training... but I suspect they just don't encounter line problems on FTTC enough to have had it ingrained properly.

In reply to a post by ukhardy07:

It all depends really. The ISP will see it as a drop in the session so to them it's a disconnection. Certainly on Sky when I was turning the router off and on (around 3 times in a couple of hours) I got put on a higher interleaving depth and lost 7Mbps of sync speed. After around 2 weeks of leaving everything on it went back to normal.

The ISP only sees PPP disconnections, but...
- The PPP layer interactions aren't monitored by the Openreach DLM, so don't cause any change to the FEC/interleaving/banding settings for FTTC
- The ISP isn't able to alter any of the FEC/interleaving/banding settings *at all* for FTTC, either manually, automatically, or even over the phone to BTw or Openreach. Whatever the ISP sees cannot be fed back to control the line settings, and are *only* information for support staff.

We have seen plenty of occasions where using a different router has made the line sync much slower with no explanation why & the line management has kicked in randomly.

I haven't yet seen a case where line management has kicked in randomly. There have been lots of cases where it kicks in because of line errors, and only a handful of cases where DLM has kicked in due to real line problems. But none that are "just" random.

I haven't yet seen a case where using a different *router* has caused any change in the *line sync* - where the sync is held by the independent modem - especially as the modem stays synced while the router changes. We've certainly seen cases where the speed changes when the modem does (eg swapping Huawei to ECI, or swapping in a single combined box like the FritzBox), but never when the separate standalone router changes alone.

Nobody seems to know the true extent of the management on FTTC as far as I'm concerned.

I'm sure there are plenty of BT R+D staff who do know this, and Ofcom/NICC staff - I've read quite a lot of the documents they put out on the subject. However, we in the public domain do not know the full extent, for sure. We're learning, as people report more information in these forums.

However, the basics *are* covered in the BT SIN documents.

I haven't yet seen anything *at all* (let alone anything compelling) that suggests FTTC DLM is affected by the PPP sessions.

In reply to a post by superspeed:

I have been doing just that for many years and for reasons above, without issue. It seems to be BT's inflexible systems that may have issue with it.

I agree - I've been turning modem/routers off on ADSL without ever triggering DLM there, and have also turned off the FTTC modem a good few times a day without ever triggering DLM there either. But then I always did both within reasonable limits, not excessively.

I understand the need for caution, though, and have certainly seen DLM intervene because of line errors.

I have an image that purports to show the BTw thresholds for ADSL2+. There the red threshold MTBR value, on a standard profile, is 144 minutes, or 2.4 hours. When averaged over 24 hours, that would be more than 10 resyncs before DLM intervenes. In reverse (the green threshold), DLM would have to see less than 5 per day before removing the intervention.

In reply to a post by superspeed:

Just found this on PN website but don't say how much will cause a problem.

Leave your router switched on
Leaving your router on will make sure you get the best speed and performance from your service.

Don�t switch it off at night! Regularly switching off your router can make it look like your service is disconnecting. If this happens, your broadband speed will be reduced because the exchange thinks your line is unstable and can�t cope with higher speeds. Speed reductions are never permanent, but it can take up to 3 days before your speeds return to normal.

http://www.plus.net/support/broadband/speed_guide/sp...

That is clearly what was written for ADSLx and hasn't been amended for fibre. It has to mean modem/router and is just using the same shorthand as most of us do. Note that it doesn't mention modems, and a router cannot connect to the internet.

As for the 3-day bit - that means it has been incorrect even for ADSL since August 2008 when the 3-day IP Profile system it refers to was replaced by a 4-hour to five day one. Which itself has now been replaced by the instantaneous 88.2% of sync on WBC/WBMC.

So don't take any notice of it.

Ummmm!!!!

On proof-reading at the Preview stage, it's even worse. Complete twaddle. The 3-day recovery thing was IP Profile, which for this discussion is only driven by connection speed, and the speed reduction side would be sync-time noise margin raising which takes/took 10-14 days per 3dB reduction.

Tripe.

So following the advice on that page have you got the microfilters fitted correctly and are you user the master socket as illustrated in the picture?

Plusnet's internal tools (they create pretty pictures of the PPP session drop/restore) will see each drop of the router, but this information is NOT used by the cabinet, DLM or Openreach. It is more used by the Plusnet support people when they want to troubleshoot your line.

Well I shouldn�t have anything to worry about if that is just PN�s software but they don�t tell you that and still say, it can affect your line speed.

Anyway thanks for your replies . No wonder you are a bright spark.

Ha ha your post made me laugh.


I did a search from google and that's what came up. I didn't take much notice of the rest of it, just wanted to see what plusnet said about turning a router on and off and how they think it affects your line. Looks like they are using the same information on fibre, even if it isn't relevant, as you say.


Looks like PN have some updating to do on their website then.

No, I have no need for filters, as I have a proper filtered socket now. It's as I said to roberto above.

Edited by deleted (Thu 03-Jan-13 16:27:10)

While we are on the subject of DLM, could someone please answer this question honestly.

Is it true that due to ofcom regulations, that DLM is required on all lines and if not, will have to be implemented?

If that is true, then that is absolutely ridiculous. Otherwise may just an excuse for isp's to keep us on DLM. DLM should be able to be turned off.

Just to a thought - Surely the whole idea of DLM to keep the line stable. I know it is a real pain, but the concept is a good one (when it works correctly). It just seems to identify everything as a disconnection

In reply to a post by superspeed:

No, I have no need for filters, as I have a proper filtered socket now.

Given that you had realised there were some things on there that didn't apply to fibre, did it not occur to you that there was a distinct possibility that none of it applied and it was written before fibre came along?

It could of applied to both or some of it. It didn't exactly say it was ADSL or fibre.
Again see what I said to roberto.

PN have been caught out with, out of date information in the past. Just look at one of my old threads.

Edited by deleted (Thu 03-Jan-13 21:24:18)

Yes that is correct and DLM is a pain but that doesn't answer my question.

I can't find anything that says, Ofcom requires isp's/wholesale, to use DLM on broadband lines.

I can't find anything that says, Ofcom requires isp's/wholesale, to use DLM on broadband lines.

More to the point have you found anything from Ofcom to say they can't?

DLM is an operator's choice to deliver the balance of speed and reliability they feel appropriate. In their spec for active line access (ALA) OFCOM say...

"Ethernet ALA shall not preclude the ALA-user from being able to define and agree,
with the ALA-provider, the specific parameters of the VDSL2 line profiles to best
support the ALA-user�s product sets. This philosophy extends to the area of
Dynamic Line Management (DLM) and Dynamic Spectrum Management (DSM)."

In other words Sky or Talk Talk should be able to arrange DLM regimes that suit them in discussion with Openreach. DLM does of course already have more than one setting in terms of how stable it tries to be. Sky seemed happy with the three currently on offer.

yeah roberto and wombat are right.

On my own connection I did dozens of router ppp disconnects in a single day as was configuring it and finding out some settings dropped ppp. This had no affect on DLM or the sync whatsoever.

I have also disconnected my modem deliberatly a few times for things such as unlocking it and swapping to an ECI modem, and always made sure I never did it more than once a day, and no affect on DLM.

I suspect the prime trigger for DLM is error counts and they need to be consistent as well, eg. if you have a burst of crc errors but it happens just once DLM wont do anything but if its an issue for many hours then it may react the next morning, excessive disconnections may also trigger things tho but one a day I know is ok.

In reply to a post by superspeed:

Yes that is correct and DLM is a pain but that doesn't answer my question.

I can't find anything that says, Ofcom requires isp's/wholesale, to use DLM on broadband lines.

DLM may be perceived to be a pain to an individual user, but the real point is that it balances usage between many users, if done properly. Full DLM doesn't just employ interleaving & error correction, but also power masking, power backoff and other techniques. They're getting a lot of research study, and are getting a lot more complicated. Try not to be so dismissive of the newer techniques based on criticism of the original ones!

The full title, Dynamic Spectrum Management, is a toolbox of techniques which work to varying effect - one of the better known "future" ones is called "vectoring" which people expect to use to counter crosstalk on FTTC lines, gaining some 20-30 Mbps for a lot of lines. *That* kind of DSM I most certainly approve of.

Anyway...

Ofcom delegates the rules for connecting equipment to BT's metallic access network to a group known as NICC. One aspect they control is the ANFP, which can be found here. The ANFP defines the power masks, which are a part of DSM techniques (but not DLM).

They haven't specified that DLM *must* be used, but they have certainly studied DLM, and specified that it *should* be used as one technique of many.

DLM as we knew it in ADSL-Max (in BT) was a variant known as AMA (changing SNR targets). DLM as it is employed in FTTC is better known as TRA (restricting speeds). The technique used in ADSL2+ (in BT) is a cross between the two.

NICC have a report on the use of DSM in the UK, with this as part of the executive summary:

In reference to www.niccstandards.org.uk/files/current/NICC%20ND%201513%20(2010-01)...:

1) DLM or DSM Level 1 is undoubtedly a useful capability for UK DSL network operators.

2) The use of the TRA approach should be considered for any DSM Level 1/DLM deployment because of its potential to lower the impact of crosstalk as well as improving overall performance (speed versus stability versus transmit power trade-off) compared with AMA. AMA was evaluated with or without the use of VN, while TRA was evaluated only without VN. Improved politeness and consequential reduction in transmit power and crosstalk levels may bring benefits to UK DSL operators and their end-users.

3) Techniques such as DSM, AL-FEC (Application Layer � Forward Error Correction) and retransmission continue to develop and DSL service providers should consider DSM Level 1/DLM as one technique within a �toolbox� of techniques available to improve DSL transmission performance and stability.

...

7) At the time of publication DSM Level 2 and 3 techniques are at early stages of implementation and analysis of their benefits in the UK access network is left for further study.

The various techniques for DLM and DSM are discussed by "The Broadband Forum" in document TR-197, "DQS: DSL Quality Management Techniques". These specification govern the protocols that the equipment manufacturers build into their equipment. The editors of that document come from Ericsson, ECI and Huawei.

In reply to a post by yarwell:

Sky seemed happy with the three currently on offer.

Nice find.

With that sort of co-operative intent, we may find that vectoring can be made to work well in the UK, rather than the kind of problems they seem to be seeing in Germany.

In reply to a post by shalom2005:

Just to a thought - Surely the whole idea of DLM to keep the line stable.

That is very much the intention - and the DLM employed under FTTC seems to aim to make the line *very* error-free.

The intent would appear to match up with delivery of triple-play, high-quality video over FTTC. That hasn't been confirmed by anything from BT, but does match up with the NICC report I just posted the link to.

interesting power back off is part of DLM now?

on my own line I am curious if power was backed off. I do know my upstream transmit power is now lower after that sync dropped.

I believe downstream transmit power is always reported the same on the cpe so the true value isnt known to the user just the upstream power.

I believe downstream transmit power is always reported the same on the cpe so the true value isnt known to the user just the upstream power.

Nah, the DSLAM signals the downstream power to the modem. If the modem didn't know the downstream power it couldn't know the attenuation.

If less tones are in use (lower sync) there's less power, as the power per tone seems to be a constant.

Only if the 3% to 4% of UK lines with sub loop unbundling agree too

In reply to a post by MrSaffron:

Only if the 3% to 4% of UK lines with sub loop unbundling agree too

Are there any cases of SLU with more than one operator on a cabinet ? BT haven't duplicated Rutland Telecom's two cabinets that I know, how about SYDR ?

That's mostly the Digital Region area, plus a couple of bits of Rutland Telecom, right?

Certainly SLU and Vectoring would appear to be contra-indicated, so it is interesting to watch whether the players (Ofcom included) will push the technology (and speed) advance over the desire for competition or vice-versa. And to watch how the competing attitudes change over time.

In Digital Region definite overlaps and there may be in Rutland.
I think there is a scattering of the odd cab here and there elsewhere that I've forgot details of

At Essendine (Rutland telecom) Openreach didn't put in a duplicate cab, though they did beat Rutland Telecom to it at nearby Ryhall.

Non-vectored lines in a vectored bundle impairs vectoring, AIUI, but doesn't affect standard VDSL2 ? So at worst a non-vectoring co-sited cabinet would deny access to the higher speeds.

In reply to a post by yarwell:

Non-vectored lines in a vectored bundle impairs vectoring, AIUI, but doesn't affect standard VDSL2 ? So at worst a non-vectoring co-sited cabinet would deny access to the higher speeds.

That's my understanding too.

In the end, it would depend on whether your most significant disturbers happen to be on the same SLU cabinet, or a different one.

Search for MR-257 from the Broadband Forum. It's a reasonable summary of the state of vectoring, 6 months old.

yes there is 3 different categories.

vectored
vector friendly - this stops impairing vectored lines but doesnt benefit itself from vectoring, the link yarwell posted with proposed low cost solutions to providers would allow all lines to become vector friendly without CPE upgrades but of course still requires cabinet equipment to be upgraded be it via firmware or hardware.
legacy - where we are now

personally I think if in situations where openreach has 2 cabinets it probably wont be a huge problem, the bigger risk from where I sit is if somehow SLU takes off, also as well if hg and eci cannot develop a solution to allow lines to become vector friendly without CPE replacements.

I wonder if the current modems already are vectoring-capable. IIRC the SIN specification for lines-only kit to be used specify it.

exactly the point I mentioned, glad someone else noticed

Thanks for the replies, information and to wombat, roberto others as well.

The reason I asked the question was, because of what PN told me. I originally called PN to ask them to turn off DLM on my line. It should of been or be as, easy as, asking for interleave to be turned on or off but it's not.

At first PN seemed sure it could be done but then they told me, that it is not possible to turn DLM off, on Fibre but can be done on ADSL. I then questioned why such a ridiculous restriction in place, to be told, that it's because Ofcom requires them to.

In my view DLM should only be used in the first ten day training period or when absolutely necessary. It should be changed.

Oh well. Anyway I will let you all and Mr saffron continue, as it's getting a bit above my head now. Lol

Edited by deleted (Sat 05-Jan-13 17:59:08)

ofcom dont require them to, its a business decision made by openreach to supply it with DLM always on to plusnet, and unless plusnet do SLU they have to supply it that way to you.

One of the problems seems to be that some people (unfortunately including some ISP support staff) incorrectly refer to the VDSL2 modem as a router.

They don't all seem to have got into the habit yet of distinguishing between the two for VDSL2 services.

It may be prudent to always ask if support staff actually mean the modem when they mention the router.

Another issue is that the modem can resync very quickly on the fly to allow DLM to take action in either increasing or decreasing sync speed, adjusting Interleaving up or down accordingly.

ISPs don't always see these resyncs as they are too quick to need to initiate a new PPP session.
In those cases, they believe a line is stable as those types of resync do not register in their logs/graphs.

That was the problem I had before unlocking my HG612 modem & developing the monitoring/graphing tool when I had to "argue" with Plusnet that my connection was very unstable when they claimed it was perfectly stable.

For a while, my connection resynced many times per hour, yet not one drop was seen by Plusnet.

No doubt BT could see the resyncs, but Plusnet would not contact them because as far as they were concerned, the connection remained stable.

This also has a side effect of resyncs not always triggering a Plusnet Line Speed profile adjustment, so users can end up stuck on a low Plusnet profile with high sync speed and low throughput or conversely still have a high Plusnet Line Speed profile despite the modem being in sync at a much lower speed.

This all makes any fault diagnosis incredibly difficult without access to an unlocked modem (preferably the HG612 as we can easily see, log and graph changing connection conditions).

This issue is not exclusive to Plusnet.

Hi,

The DLM cannot be turned off , we can configure settings with the DLM to be more lenient when required.

@Bald_Eagle1
Are you still seeing drops on your connection?

In reply to a post by chrispurvey:

we can configure settings with the DLM to be more lenient when required.

Hi Chris,

Is that a new development? How is "required" defined and what settings can you change?

we can configure settings with the DLM to be more lenient when required.

Can you say more about the three options you have ?

In reply to a post by chrispurvey:

@Bald_Eagle1
Are you still seeing drops on your connection?

Thanks for asking Chris, but no. That was all eventually resolved last May (I thought).
It turned out to be a combination of a defective VDSL2 SSFP filter & a really fragile joint between the pole top DP & the underground D-side cable that simply snapped off when the engineer went to check it.

However, since 31st December, I have seen a sudden drop in my attainable rates & just the one the fly resync lowered my sync speed by around 3Mb to 25746 kbps.

Prior to the resync, my DS SNRM was unusually running at around 2.8dB (from its usual really steady 6dB).

DS SNRM is at a steady 6dB again now, but DS Attainable rate has reduced from 33596 kbps to its current 30216 knps.

I did force a resync to no avail.

So, I was intending to wait until a couple of weeks after Christmas rather than keep resyncing the connection, just in case this deterioration had been caused by tree lights etc.

If things don't pick up again, I will be asking for it to be looked into as I can see quite a deterioration in my internet "experience".

I'm sure that getting Plusnet/BT to look into it won't be any easy matter to instigate as I would expect to see the usual "the connection is operating within acceptable limits" type of responses again.

In reply to a post by yarwell:

we can configure settings with the DLM to be more lenient when required.

Can you say more about the three options you have ?

In here

http://www.openreach.co.uk/orpg/home/products/super-...

yeah the speed (gamer) profile, which is the one zen apparently default to.

To RobertoS thats also how I know that they all start on 6db but its the sensitivity that changes depending on the profile configured.

In reply to a post by systemx:

In reply to a post by yarwell:

we can configure settings with the DLM to be more lenient when required.

Can you say more about the three options you have ?

In here

http://www.openreach.co.uk/orpg/home/products/super-...

Yes, I know about all that, but (most) ISPs, including Plusnet, had previously denied that they could change it. Chris has now said that they can, although he didn't mention three options, that was yarwell.

In reply to a post by superspeed:

Yes that is correct and DLM is a pain but that doesn't answer my question.

I can't find anything that says, Ofcom requires isp's/wholesale, to use DLM on broadband lines.

I will complaint to ofcom and asked ofcom to tell BT to get rid of DLM. Because DLM is evil things to quickly reduced your sync rate and push interleaved on.

DLM is pure evil by BT.

In reply to a post by superspeed:

I have always turned it off and for security. No way am I leaving my computer connected to the web 24/7. Power is getting more expensive and it's a waste of energy but I know what you are saying.

Your computer isn't connected to the web. It's connected to your router. The outside world doesn't even have an IP address for your computer.

The outside world can only attack your computer if you have chosen to initiate a conversation or if it's a server and you are using port forwarding. This is the inherent security of NAT ( https://www.grc.com/nat/nat.htm ). Now if/when Plusnet ever get their act together and roll out IPv6 (like some other ISPs eg AAISP, IDNet did a couple of years ago) your computer will have a a public facing address so can be targeted. But attacks will still have to through your router which will (should!) have a firewall.

I think most people would take the view that you are being excessively paranoid and possibly depriving yourself of some of the benefits of your connection by switching the router off when you're not actively using the internet. I think it's akin to unplugging all your appliances when you go to bed to avoid lightening strikes

In reply to a post by superspeed:

That's good if you can get that speed but you can't beat a wired only connection. Much less hassle.

Now there I agree. Wireless is good if you have to be mobile but I all the places I'm likely to sit down with my laptop have a convenient Ethernet cable. Only my phone uses my wifi for any length of time.

Second best would be a pair of homeplugs, one in the router and the other you take with you to wherever in the house you need the connection.

Second best would be a pair of homeplugs, one in the router and the other you take with you to wherever in the house you need the connection.

That should work in theory, but another user recently tried it and found very poor speeds, even though the powerlines themselves were capable of decent speeds in 'normal' use within the LAN.

I can't remember where the post was can can't find it again. There were various suggestions such as larger packets or a different pattern of packets; the LAN sees regular internet packets and the modem/router connection has them PPPoE encapsulated.

In reply to a post by adslmax:

In reply to a post by superspeed:

Yes that is correct and DLM is a pain but that doesn't answer my question.

I can't find anything that says, Ofcom requires isp's/wholesale, to use DLM on broadband lines.

I will complaint to ofcom and asked ofcom to tell BT to get rid of DLM. Because DLM is evil things to quickly reduced your sync rate and push interleaved on.

DLM is pure evil by BT.

I notice this thread is over 20 months old but as a matter of interest have you as an individual had any complaints upheld by Ofcom in the past?